Had the same problem, you most likely will need to start a new corner post and build around the cliff until you are able to seal it off at some point. OR you can ask Jorb nicely to remove or move the cliff like he did at one time for Sodom.
I can't really do either of those things, especially because it will take over 500 logs to go around the cliff. How about an oven? Those seem pretty robust.
rope is easy to get, dry some skins and use them, glue even easier. leather 10, shouldn't be too hard. logs.....very easy. no more than a day if you get started now.